Immunoglobulin A (IgA) nephropathy is the most common type of primary glomerulonephritis in the world. The treatment of IgA nephropathy with normal renal function and minimal proteinuria is unknown. Since angiotensin-converting enzyme (ACE) inhibitors reduce proteinuria and retard the rate of decline of renal function in chronic proteinuric nephropathies, including IgA nephropathy. The investigators conduct a randomized control study to evaluate the efficacy of ACE inhibitor in the treatment of early IgA nephropathy. Sixty patients with biopsy-proven IgA nephropathy and minimal proteinuria are recruited. They will be randomized to ramipril for 5 years or no treatment. Blood pressure, proteinuria and renal function will be monitored. This study will explore the effects of ACE inhibitor in the treatment of early IgA nephropathy, which is a major cause of dialysis-dependent renal failure.